fletcher



(No Model.) 6 Sheets-Sheet 2.

G. FLETCHER & W. P. ABELL. GUT-OFIF MECHANISM FOR SLIDE VALVES.

No. 485,267. Patented Nov. 1, 1892.

23 5365. gi/fntam" flamr94,

(No Model.) 6 Sheets-Sheet 3. G". FLETCHER 85 W. P. ABELL. GUT-OFFMECHANISM FOR SLIDE VALVES- No. 485,Z67. Patented Nov. .1, 1892.

(No Model.) 6 Sheets-Sheet 4.

G. FLETCHER 8: W. P. ABELLr GUT-OFF MEGHANISM FOR SLIDE VALVES. No.485,267.

Patented Nov. 1, 1892.

tin/65565. M

(No Model.) 6 Sheets-Sheet 5.

G. FLETCHER 8: W. P. ABELL.

GUT-0FF MECHANISM FOR SLIDE VALVES.

No, 485,267. Patented Nov. 1, 1892.

Wi/Znesscs. lfivenars I (No Model.) 6 Sheets-Sheet 6.

G. FLETCHER 8: W. P. ABELL. GUT-0F]? MECHANISM FOR SLIDE VALVES.

No. 485,267. PatentedNov. 1, 1892.-

iigja UNITED STATES PATENT OFFICE.

GEORGE FLETCHER, OF DERBY, ENGLAND, AND WILLIAM PRICE ABELL, OFESSEQUEBO, BRITISH GUIANA.

CUT-OFF MECHANISM FOR SLIDE-VALVES.

SPECIFICATION forming part of Letters Patent No. 485,267, dated November1, 1892.

Application filed November 18, 1891. Serial No. 412,333- (No model.)

United States Letters Patent, dated November 18,1884, No. 308,181,granted to J. H. Man,

and in which cut-off valves adapted to be closed by differentialpressure are employed.

The object of our present invention is to provide improved means forcontrolling the movements of such valves and principally to effect thepositive opening of the same; and to this end it comprises theimprovements hereinafter described.

In the accompanying drawings, Figures 1 and 2 are an elevation andsectional plan of a valve-chest and a slide-valve provided with ourimprovements. Figs. 3 and 4 are respectively an elevation and atransverse section of a modification of part of the same. Figs. 5 and 6are views similar to Fig. 2, illustrating slight modifications. Figs. 7and 8 are a sectional elevation and transverse section, respectively,illustrating another modification. Fig. 9 is a sectional plan showing aslide-valve provided With two cut-off valves having double faces anddouble seats. Fig. 10 is an elevation showing an arrangement ofs1ide-valves and cut-ofi valve suitable for a vertical engine, and Fig.11 is an elevation showing another arrangement of valves suitable for avertical engine. Figs. 12 and 13 are a sectional elevation andtransverse section, respectively, showing a slide-valve provided withtwo cut-off valves of similar construction, but arrangedin a differentmanner to those shown in Fig. 6. Fig. 14 is a sectional plan showing aslide-valve provided with a single cut-01f valve having double faces anddouble seats. Fig. 15 is a view showing a stationary cut-off valve.

Similar letters of reference indicate correspondin g parts in theseveral figures.

a a indicate the slide-valves; b b, passages therein through which themotive fluid passes to the induction-ports of the cylinder; co, thecut-off valves for controlling the flow of motive fluid through the saidpassages, and d d two-faced or double cam-surfaces or tappets or stopswhich regulate the operation of the cut-oft valves.

As shown in Figs. 1 and 2, the cut-off valve 0, which is provided with arecess between its two faces, is adapted to slide upon a spindle e, soas to close one or the other of the ports or openings f, communicatingwith the passages b, and the tappet d, which projects into the saidrecesses, is of a wedge or cam shape and is mounted upon a shaft 9 insuch a manner that by rotating the said shaft 9 the tappet can be movedaccording to the cut-off required. This shaft g is connected with thegovernor of the engine, so that the position of the tappet d isregulated according to the speed of the engine. hen the slide-valve isin motion and the cut-off valve 0 rests loosely on the spindle c, itwill travel in the same direction as the slide-valve until one of itsends comes into contact with the tappet cl. During the further movementof the slidevalve the spindle e slides through the cut-off valve untilthe seat around one of the openings of a passage b comes so close to thesaid valve that the velocity of the steam or air flowing into thepassage, together with the difference of pressure in the passage and inthe valve-chest, causes one end of the cut-0d valve to close against itsseat to cut off the supply of motive fluid. The valve will then remainclosed and travel with the slide-valve go until the motion of the latteris reversed. ()n the return stroke the other end of the cut-off valvecomes into contact with the tappet, thereby drawing the end of the valvefirst referred to away from its seat, and so on, the 5 same movementstaking place alternately at opposite ends of the valve. \Vhen the tappetis in such a position that only the thin end or apex comes into contactwith the valve, the said cut-oft valve will come to rest later than IOOif it came into contact with the wider part of the said tappet, therebyallowing a longer period of time to elapse, and consequently a greaterportion of the piston-stroke to be per: formed before the motive fluidis cut off.

In Figs. 3 and 4E the tappet is shown con-- structed so as to come intocontact with the cut-off valve at two pointsone on each side of thespindle einstead of at one point, as shown in Figs. 1 and 2. By thisarrangement the shock caused by the cut-off valve striking the tappet ismore equally distributed and the tendency to damage decreased.

In Fig. 5 the valve or is shown provided with recesses a, into whichbosses or projec tions 0. on the cut-off valve are designed to enter andfit, the air or vapor contained in the said recesses serving as acushion to lessen the shock of the cut-off valve againstits seats whenclosing. Instead of utilizing the air or vapor as a cushion we mayemploy in the recesses a springs of metal or elastic material, such asindia-rubber.

In the modification of ourinvention shown in Fig. 6 the arrangement issubstantially the same as that hereinbefore described, except thatguide-flanges h are arranged around the openings to the passages b, inorder to direct the steam or air so as to flow over the edges of theends of the cut-off valves rather than to flow into the said openingsfrom all directions, thereby insuring a greater sensitiveness and moreimmediate action than would otherwise. be obtained.

In Figs. 7 and 8 the tappet d, instead of being connected to the rotaryspindle g, is connected directly to the governor-spindle, by which it israised and'lowered, the bottom end of the said tappet being held inposition by means of a guide-bracket Z. The action of the valve in thiscase is the same as that hereinbefore described.

In the arrangement shown in Fig. 9, instead of using a single valve, ashereinbefore described, we employ two eut-off valves, one in connectionwith each passage 6. In this case the closing of the valves is effectedby the use of a double-ended lever m, the inclination of which regulatesthe point at which the closing shall take place. The opening of thecutoff valves is effected by means of the adj ustable stops d d in thewalls of the valve-chest.

In the arrangement shown in Fig. 10, which is especially applicable foruse in a verticalcylinder engine, the cut-01f valve is represented asmoving in a line at right angles to the line of motion of theslide-valve. The tappet cl is in this case similar in construction tothe lever m, described with reference to Fig. 9; but the valve 0,instead of striking directly upon the ends of the said tappet, strikesthe same upon the sides and then slides along it.

In the arrangement shown in Fig. 11, which also represents a slide-valvehaving a cut-off valve moving in a line at right angles to the the lineof motion, the tappet (Z is at one end of a bell-crank lever, which isfree to move upon a pin or stud n,fixed to the slide-valve.

The end of the bell-crank lever which does not serve as the tappet isslotted,as at 0, and is free to move about a movable pin 19. When theslide-valve a is in a central position, the tappet end of the bell-cranklever will be in a vertical position and the slotted end in a horizontalposition, and if a reciprocating motion is given to the slide-valve thetappet end of the said lever will deviate to the righthand side of thevertical line when the valve is moving upward and the left-hand sidewhen the valve is moving downward. The amount of deviation depends onthe distance of the pin 19 from the vertical center line of theslidevalve, thus determining the position of the cut-off valve. Thepin 1) is moved in the slot 0 by means of the governor.

In the arrangement shown in Figs. 12-and 13 the slide-valve a isprovided with two outoff valves 0 0, arranged and operating at rightangles to the line of motion of the slide-valve. Each valve 0 isprovided with a spindle e, projecting through the top of one of thepassages b b, and the inclined surfaces 01 d are stationary, thespindles of the cut-off valves during the reciprocation impingingagainst the said inclined surfaces, whereby the valves 0 c are caused toopen. 9 is a spindle con nected to the engine-governor and having asleeve q free to slide upon it, so as to move with the valve a, butworking on a featherkey, so as to turn with the said spindle. Integralwith the sleeve q are two small levers r T, which when the spindle g isturned by the governor adjust the position of the cutoff valves 0 a sothat the pressureof steam" closes them, the two faces of each valve being of different areas to enable this to be effected. When theslide-valve a in moving nears one end of the valve-chest, the spindle enearest the said end comes into contact with the inclined surface d,also at the said end, and causes its valve 0 to open, the amount of suchopening being controlled by one of the levers r.

In the arrangement shown in Fig. 14 the cut-01f valve is provided ateach end with double faces 0 c and double seats, and is operated upon acam or tappet d, similarly to the valve shown in Fig. 1. In thisarrangement, however, the steam flows into the passages 1), past the twofaces 0 and c at each end of the valve, as in the arrangement shown inFigs. 6, 9, and 10.

In Fig. 15 the cut-off valve 0 is represented as a stationary valve, itbeing secured by a bracket 0' to the wall of the valve-chest.

Having now particularly described and ascertained the nature of our saidinvention and in what manner the 163.1116 is to be performed, we declarethat what we claim is- 1. The combination of a main valve provided withsteam-passages and having ports facing each other with a cut-off valvecarried by such main valve and retarded in its movements by a tappetwhose position is controlled by the governor and whereby when said portsare severally sufficiently near the cut-off valve the differentialpressure of the steam will cause the cut-0E valve to move and close theport.

2. The combination of the main valve having passages 12 19 therein andopenings ff, a spindle e, on which is the cutoff valve 0 c, and anadjustable tappet d, the combination being and operating substantiallyas set forth.

3. In combination with the main valve having the described passages andopenings therein and with the spindle and an adjustable tappet, a doublecut-off valve between the two openings or ports, all substantially asset forth.

4. In combination, the main valve having the described passages andopenings or ports therein, the spindle carrying adoublecut-oif

